The present invention relates to an arrangement for enhancing the cooling capacity of portable personal computers. More particularly, the invention is directed to the provision of an arrangement for increasing the cooling capacity of portable personal computers, particularly such as laptop or notebook computers. The computer possesses a keyboard having the rear edge thereof hingedly connected with the bottom of an openable display unit or panel, and containing heat-generating computer electronics, from which heat is removed through a heat pipe terminating in a coupling arrangement possessing elements which connect to and disconnect from each other when, respectively, docking and undocking the portable personal computer in a docking station so as to facilitate the transference of heat from the portable personal computer through the coupling arrangement into the docking station from whence the heat is dissipated to the surroundings through the intermediary of a heat sink.
Commencing from the time of conception and design development of computers, and especially portable personal computers; for instance such as laptop computers or the like, there has been encountered the aspect of thermal management as a result of heat which is generated by the processor and other electronic components of the computer. As is widely known in the computer technology, excessive amounts of heat can readily degrade the performance of computers, and additionally may cause the components of the computers to be damaged. Consequently, thermal management is frequently considered to be an extremely important aspect in the design and development of computers.
The capacity and performance of portable personal computers, such as laptop computers, notebook computers or the like, has recently been enhanced to such an extent that; for example, since the beginning of 1996, the thermal dissipation requirements of portable personal computers (PCS) have increased from about 10 watts to 25 watts and even higher values. This increase in the thermal dissipation requirements is a result of ever increasing CPU performance and additional functionality; such as DVD, modem, audio and the like, which are provided by future PCS. As elucidated in an article by Albert Yu, "The Future of Microprocessors", IEEE Micro, December 1996, pages 46 through 53, the trend of increasing power dissipation in the form of heat for portable personal computers will continue in the foreseeable future. Thus, at the widely employed A4 form factor for a portable personal computer; in essence, a 297 by 210 mm footprint, for instance, the cooling limit for a portable PC without an active cooling device, such as a cooling fan or providing additional passive cooling capacity is currently approximately 15 to 20 watts.
Although cooling capacity can be added through the installation of an active cooling device, such as a fan, this is normally not desirable inasmuch as these devices take up space, consume power and generate noise. Particularly in a portable personal computer, space and battery consumption and service life are at a premium, and the generating of noise is deemed to be highly undesirable. As a result, active cooling devices have been employed as a last resort in attempts to obtain additional cooling capacity. In contrast therewith, passive cooling methods and arrangements are considered to be most desirable and efficient since they do not consume any power, generate no noise and quite often take up no additional space. Thus, providing a greater cooling capacity than the current limits in order to meet the anticipated thermal dissipation requirements of future portable personal computers, represents not only a potential competitive advantage in industry, but also provides a significant product differentiation from currently available and commercially sold portable personal computers.
In particular with regard to the power consumption of laptop computers, there has been recently a continued increase in the power of the CPU. For example, the total of power of a laptop computer is normally about 10 watts, and has now increased to a range of about 30 to 40 watts or higher, whereas the CPU power has been increased from about 2 to 6 watts and, conceivably, can be as high as in the 10 watt range. Most of this power will eventually be dissipated in the form of heat to the surroundings. Consequently, being able to remove increased amounts of heat from the laptop computer becomes a critical factor in the construction and operation of such laptop computers.
One approach to solving the heat load problem is to run the processor chip, which is usually the greatest heat generator, at two different clock speeds, a slow speed which generates less heat, when the portable personal computer is used in a mobile environment, and a faster, hotter state when used in an immobile environment, such as when used in a docking station, where power and space is abundantly available. This allows the user to use the full speed of the processor while at a docking station where the full power of the computer is most often needed and at the same time the user can use the computer in a mobile state, i.e. powered by battery only and without a docking station, with the processor running at a reduced rate to minimize heat generation. In order for this approach to work, means for dissipating additional heat is needed when the computer is installed in a docking station.